Antioxidative activity and total phenolic compounds of

1 downloads 6 Views 199KB Size Report
Natural antioxidants from rosemary and sage. Journal of. Food Science, 42 ... Gardner, P. T., White, T. A. C., McPhail, D. B., & Duthie, G. G.. (2000). The relative ... Free Radical Biological and Medicine, 20(7), 933–956. SAS Institute, Inc. (1990) ...

Food Chemistry 81 (2003) 575–581 www.elsevier.com/locate/foodchem

Antioxidative activity and total phenolic compounds of leaf, root and petiole of four accessions of Centella asiatica (L.) Urban M.K. Zainola, A. Abd-Hamida,*, S. Yusofb, R. Musec a Department of Food Science, Universiti Putra Malaysia, UPM 43400, Serdang, Selangor, Malaysia Department of Food Technology, Faculty of Food Science and Biotechnology, Universiti Putra Malaysia, UPM 43400, Serdang, Selangor, Malaysia c Department of Biochemistry and Microbiology, Faculty of Science and Environmental Studies, Universiti Putra Malaysia, UPM 43400, Serdang, Selangor, Malaysia b

Received 8 April 2002; received in revised form 28 October 2002; accepted 28 October 2002

Abstract Antioxidative activity and total phenolic compounds of root, leaf and petiole of four accessions of Centella asiatica (L.) Urban, namely CA 01, CA 05, CA 08 and CA 11, were evaluated. Antioxidative activity of the extracts was measured using the ferric thiocyanate (FTC) method and thiobarbituric acid (TBA) test. The antioxidative activities were then compared with that of a-tocopherol (natural antioxidant) and butylated hydroxytoulene or BHT (synthetic antioxidant). The results showed that CA 01 and CA 05 had the highest antioxidative activities among the accessions tested. Results also showed that both leaf and root of C. asiatica had high antioxidative activity, which was as good as that of a-tocopherol. The total phenolic content, determined according to the Folin–Ciocalteu method, varied from 3.23 to 11.7 g/100 g dry sample, and showed strong association (r2=0.90) with antioxidative activity. The results suggest that phenolic compounds are the major contributors to the antioxidative activities of C. asiatica. # 2003 Elsevier Science Ltd. All rights reserved. Keywords: Centella asiatica; Antioxidative activity; Ferric thiocyanate; Total phenolic content

1. Introduction Centella asiatica or ‘pegaga’ is one of the local herbs that is claimed to possess various physiological effects. Reports from different places have revealed that C. asiatica has been used for wound healing, memory improvement, treating mental fatigue (Goh, Chuah, & Saepadmo, 1995), bronchitis, asthma, dysentery, leucorrhoea, kidney trouble, urethritis (Jaganath & Ng, 1999), antiallergic and anticancer purposes, curing leukorrhea and toxic fever (Kan, 1986). It is also commonly used as a porridge for feeding pre-school children in Sri Lanka in combating nutritional deficiencies (Cox, Rajasuriya, Soysa, Gladwin, & Ashworth, 1993). Even though this precious herb is surrounded with various claims, the underlying mechanisms involved in its physiological effects are lacking. More scientific data are required before recommendation for increase in its consumption/utilization can be given with confidence. * Corresponding author. Tel.: +60-3-89486101x8374; fax: +60-389423552.

The oxidative deterioration of lipid-containing food is responsible for the rancid odours and flavours during processing and storage, consequently decreasing the nutritional quality and safety of foods, due to the formation of secondary, potentially toxic compounds. The addition of antioxidant is a method for increasing the shelf life of foods. Antioxidative activity of phenolic compounds is based on their ability to donate hydrogen atoms to free radicals. Many phenolic compounds, particularly flavonoids, exhibit a wide range of biological effects, including antibacterial, antiviral, and antiinflammatory, anti-allergic, anti-thrombotic and vasdilatory actions (Cook & Samman, 1996). Studies have also shown that some of these compounds are potent scavengers of free radicals and, as such, are potentially useful in the prevention of arteriosclerosis, cancer, diabetes, neurodegenerative diseases, arthritis and others. Protective effects of diets high in fruits and vegetables have been attributed to the presence of these compounds. Synthetic antioxidants have restricted use in food as various studies have shown them to be carcinogenic

0308-8146/03/$ - see front matter # 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S0308-8146(02)00498-3

576

M.K. Zainol et al. / Food Chemistry 81 (2003) 575–581

Fig. 1. Antioxidative activities of leaves, roots and petioles of different accessions of C. asiatica (L.) Urban, as measured by the FTC method. Absorbance values represent triplicates of different samples analysed. Values with the same letter (a, b, c) are not significantly different (P

Suggest Documents